Background: The herbal antidiabetic drugs are safe but effective alternate to conventional oral antidiabetic therapy. The single phytoconstituents of single plants are inadequate to produce the required efficacy therefore polyherbal can be tested for the desired results. The objective of the present study was the assessment of total phenolic, flavonoids, tannins content, in vitro antioxidant and antidiabetic activity of Azadirachta indica leaves, Picrorhiza kurroa rhizomes, Pterocarpus marsupium heartwood, and Withania coagulans berries and fruit coat. Materials and Methods: The ethanolic extract of all four drugs were prepared and mixed in a ratio of 1:1:1:1 to make the polyherbal extract. It was checked for the presence of phenols, flavonoids, and tannins. The High-Performance Liquid Chromatographic (HPLC) analysis for phenolic compounds as well as the beta carotenoids was done. The in vitro antioxidant activity as well as in vitro antidiabetic activity were calculated. Results: Quantitative estimations showed that maximum phenolic content was in Azadirachta indica and Pterocarpus marsupium, the flavonoid in Withania coagulans, and tannins content in Pterocarpus marsupium. The HPLC analysis showed the marked presence of beta carotenoids along with other phenolic compounds. The radical scavenging activity of Pterocarpus marsupium and the polyherbal extract was comparable to the standard Gallic acid. The total antioxidant capacity of polyherbal extract was found to be 15.22±.051 mg Quercetin equivalent (QE)/g dry plant extract (DPE). The polyherbal extract showed an IC50 value of 58.81 μg/ml in case of α- amylase inhibition and 64.81 μg/ml in case of α- glucosidase inhibition. Conclusion: The antioxidant activity, as well as antidiabetic activity, may be attributed to the phenolic, tannins, flavonoid content as well as beta carotene found in the polyherbal extract.
Keywords: Azadirachta indica leaves, Pterocarpus marsupium heartwood, Picrorhiza kurroa rhizomes, and Withania coagulans berries and fruit coat, Antioxidant, In vitro antidiabetic.